


Erebor: A Modern Marvel

by TexasDreamer01



Series: Erebor Engineering [1]
Category: TOLKIEN J. R. R. - Works & Related Fandoms, The Hobbit - All Media Types
Genre: Animated GIFs, Dwarves, Embedded Images, Engineering, Erebor, Formulae, Gen, Headcanon, Inspired By Tumblr, Originally Posted on Tumblr, Worldbuilding
Language: English
Status: Completed
Published: 2017-05-18
Updated: 2017-05-18
Packaged: 2018-11-02 07:18:25
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,733
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/10939650
Author URL: https://archiveofourown.org/users/TexasDreamer01/pseuds/TexasDreamer01
Summary: Erebor is considered a pinnacle of practical art - but how would it look, and function, with real-world engineering principles applied to it?





	Erebor: A Modern Marvel

**Author's Note:**

> Originally posted on [tumblr](http://texasdreamer01.tumblr.com/post/121177889400/motherfuckingbagginshield-inja-y-ddraig). Since this work focuses on what I wrote myself, the lead-up context is missing from here, though I'm keeping the tumblr-style prose in lieu of that.
> 
>  **TL;DR** \- What if Dwarves were steampunk, had animals and trains and an underground river? ... Nah. Well. _Sort of_.

WHAT IF they used a pressure-based exhaust system for their ventilation? This would incorporate the use of steam - derived from an underground hydroelectric dam (I think that’s what you were going for?), solve the problem of being an enclosed building with little windows and fewer doors to the outside, and make use of an underground river to generate electricity (because let’s face it, electricity is _probably_ a thing; they have all the copper they need to make wires). Oh, and pollution and condensation. Terrible things, ruins your home and makes you late for dinner.

An underground railway - or any other means of transportation like coaches or buggies or rickshaws or what have you, ventilation, plumbing, regulation of temperature in the entire mountain, food production, running the forges, even a _**communications system**_ is all perfectly feasible. _If_  you assume there’s an underground river (and there’s such a high chance of that with the River Running that I’m going to take it as canon), which means all of this is possible via the means of said underground river being used to have a hydroelectric plant.

Steam? It’s a pretty idea (steampunk is hella cool), but it has the downside of producing a lot of condensation that can and _will_ deteriorate stone over time. If you stick it in pipes and pressurize it, that’s great, but open systems with lots of bellowing plumes of steam will compromise the structural integrity of Erebor and thus = No.

I don’t think there’s waterfalls, if only because that means there’s giant caverns in the basement of the mountain and that means stone like limestone - caves are cool, not so great for supporting a population of a few thousand that constantly inhabit the upper reaches of the mountain. Besides the fact, Erebor’s _green_ , which means it’s either some form of granite or marble. As the latter has a Mohs hardness scale of _three_ , it’s hella easy to carve and thus unlikely to be the majority of the stone in the mountain. Granite, however, is an igneous rock, which means that it was formed from the slow crystallization of magma below Earth’s surface - I don’t think there’s a volcano, but a magma pocket is likely, along with the mountain range being formed by plate tectonics.

[ **EDIT** : I've found a better rock! Check out lherzolite on the Imperial College of London's [Rock Library](https://wwwf.imperial.ac.uk/earthscienceandengineering/rocklibrary/viewglossrecord.php?Term=lherzolite); [Wikipedia](https://en.wikipedia.org/wiki/Lherzolite) has an [image](https://en.wikipedia.org/wiki/Lherzolite#/media/File:Garnet_lherzolite_-_xenolith_from_a_kimberlite_pipe,_Kimberley_SA.jpg) specifically of garnet lherzolite. Eventually I'll be writing a separate post on this, but as both granite and lherzolite are igneous rocks, most of the following information on granite is still applicable.]

Pulling from [geology.com](http://t.umblr.com/redirect?z=http%3A%2F%2Fgeology.com%2Frocks%2Fgranite.shtml&t=MDA5M2MzZGEzYTQzY2FmOTQ2YjY5OGFmOWM4ZGYwZThjMGQ0NTNmMixrRkQ2QUdZZQ%3D%3D&b=t%3AYnEewNG4oBRl9M0gUhrDsA&p=http%3A%2F%2Ftexasdreamer01.tumblr.com%2Fpost%2F121177889400%2Fmotherfuckingbagginshield-inja-y-ddraig&m=1) (gorgeous website, lots of information about minerals, metals, and the like): 

> Granite is the rock most often quarried as a “dimension stone” (a natural rock material that has been cut into blocks or slabs of specific length, width and thickness). Granite is hard enough to resist most abrasion, strong enough to bear significant weight, inert enough to resist weathering and it accepts a brilliant polish.

Very sturdy.

Now, as for the river, the probable lack of waterfalls mean that there’s a low head – and I’m gonna take a shot in the dark here and guess that the name “River Running” means a fast moving river, so that means a high flow. This is usually bad for a regular hydroelectric dam, because it relies on high head to gather kinetic energy that can be transferred into its generators as potential energy.

The solution to this would be to utilize an Archimedean screw type of turbine.

For reference, this is how a more common type of hydroelectric plant operates:

As you can see, it’s vertical, which is good when you’re making dams near waterfalls that take advantage of all that kinetic energy. However, an underground river is _underground_ , and likely doesn’t have the same advantages. An Archimedean screw solves this problem by going at an angle like so:

Depending on which way it’s rotating, the water either goes up, or down. The crank can be attached to a gear, which can create a loop that uses the electricity generated by the dam to power the dam itself. Nice, neat, compact system [with almost no carbon footprint](http://t.umblr.com/redirect?z=https%3A%2F%2Fwww.edfenergy.com%2Fenergyfuture%2Fenergy-gap-climate-change%2Fhydro-marine-and-the-energy-gap-climate-change&t=NGQ1NDJmNDNmY2U5Mjg3ZDg2OTcxYTUxYmQ1YTAxYWMxMGM3M2Q0MyxrRkQ2QUdZZQ%3D%3D&b=t%3AYnEewNG4oBRl9M0gUhrDsA&p=http%3A%2F%2Ftexasdreamer01.tumblr.com%2Fpost%2F121177889400%2Fmotherfuckingbagginshield-inja-y-ddraig&m=1). Quite Dwarvish, yes?

Kinetic energy (from the river itself) -> mechanical energy (from the turbine) -> potential energy that can be stored in generators.

Using the imperial system, you can calculate the amount of kilowatt hours this produces with the following formula:

> **Power** = (Height of Dam) x (River Flow) x (Efficiency) / 11.8

Where

> **Power**   The electric power in kilowatts (one kilowatt equals 1,000 watts).
> 
> **Height of Dam**    The distance the water falls measured in feet.
> 
> **River Flow**    The amount of water flowing in the river measured in cubic feet per second.
> 
> **Efficiency**    How well the turbine and generator convert the power of falling water into electric power. For older, poorly maintained hydroplants this might be 60% (0.60) while for newer, well operated plants this might be as high as 90% (0.90).
> 
> **11.8**    Converts units of feet and seconds into kilowatts.

There’s examples from the [Wisconsin Valley Improvement Company](http://t.umblr.com/redirect?z=http%3A%2F%2Fwww.wvic.com%2FContent%2FHow_Hydropower_Works.cfm&t=ZDA2NzBiMWJjOTJiOWViN2Q3YTdhNTgwMjRiOWQyYjNlMTE1NWQxNCxrRkQ2QUdZZQ%3D%3D&b=t%3AYnEewNG4oBRl9M0gUhrDsA&p=http%3A%2F%2Ftexasdreamer01.tumblr.com%2Fpost%2F121177889400%2Fmotherfuckingbagginshield-inja-y-ddraig&m=1), where the formula and gif of the hydroelectric plant is pulled from, that gives you an example of how many kilowatts a given plant can generate, as well as how many people it can service per a certain amount of kilowatt-hours per person.

An Archimedean screw turbine is also [highly efficient](http://t.umblr.com/redirect?z=http%3A%2F%2Fwww.renewablesfirst.co.uk%2Fhydro-learning-centre%2Farchimedean-screw%2F&t=MWE5OGY4ZWFkZDk1ZjhmNDM3YWZhYTQ0ZDM4Y2UyZmZjMjkyMjBkYixrRkQ2QUdZZQ%3D%3D&b=t%3AYnEewNG4oBRl9M0gUhrDsA&p=http%3A%2F%2Ftexasdreamer01.tumblr.com%2Fpost%2F121177889400%2Fmotherfuckingbagginshield-inja-y-ddraig&m=1), with a stabilized mechanical efficiency ranging from 80% - 90%:

A well-made turbine of this design can have a working life exceeding [100 years](http://t.umblr.com/redirect?z=https%3A%2F%2Fwww.edfenergy.com%2Fenergyfuture%2Fenergy-gap-climate-change%2Fhydro-marine-and-the-energy-gap-climate-change&t=NGQ1NDJmNDNmY2U5Mjg3ZDg2OTcxYTUxYmQ1YTAxYWMxMGM3M2Q0MyxrRkQ2QUdZZQ%3D%3D&b=t%3AYnEewNG4oBRl9M0gUhrDsA&p=http%3A%2F%2Ftexasdreamer01.tumblr.com%2Fpost%2F121177889400%2Fmotherfuckingbagginshield-inja-y-ddraig&m=1), with a design life of approximately [30 years](http://t.umblr.com/redirect?z=http%3A%2F%2Fwww.renewablesfirst.co.uk%2Fhydro-learning-centre%2Farchimedean-screw%2F&t=MWE5OGY4ZWFkZDk1ZjhmNDM3YWZhYTQ0ZDM4Y2UyZmZjMjkyMjBkYixrRkQ2QUdZZQ%3D%3D&b=t%3AYnEewNG4oBRl9M0gUhrDsA&p=http%3A%2F%2Ftexasdreamer01.tumblr.com%2Fpost%2F121177889400%2Fmotherfuckingbagginshield-inja-y-ddraig&m=1).

> **TL;DR** – A small hydroelectric plant can generate enough electricity to sustain nearly a thousand people at modern levels of electrical usage. Given that Erebor doesn’t have a population that frequently has computer/TV/etc users, this can be divided out to an even _greater_ number of people. It is sustainable, has a sufficient output, requires little maintenance, and is complementary to a number of other technologies that require a form of energy – be it electricity, pressure via steam/water piping, or a convection system – that also prevents an increase in pollution from the housing of domesticated animals and burning of fuels in an enclosed space.

That’s right – convection.

Air, and in this case _heated_ air, solves the problem of ventilation, food production, a communication system, and regulating the temperature of the mountain.

Because there’s about zero windows and presumably only two doors to the outside (back door and snazzy front gates), cracking one of them open isn’t going to coax sufficient air flow and prevent the inhabitants from suffocating from their own respiration. Even if they _did_ have a bunch of chutes to funnel air in and out of the mountain, that presents too many problems – there’s not enough pressure to move the stale air out, and constantly working manually-driven fans to produce sufficient air flow is going to require too much manpower to make a whole lot of sense.

First thought is an exhaust system, yes? Pipe in, pipe out, uses some form of heating system and the exhaust just takes all the extra out.

… Cold air from the exhaust causes an inefficiency and creates the problem of adequate heating of the mountain – and besides the fact, it’s a system generally used for small homes that is difficult to scale up without creating waste (such as needing to stick a heat source like a radiator or a fireplace right next to the exhaust to ameliorate the piss-poor design). This also induces a structural integrity problem in that too much excavation for ventilation can fundamentally destabilize the mountain – sturdy granite or not.

There’s a two-pronged route that can be taken to solve this problem. One part is to use a supply and exhaust air systems with heat recovery ventilation system to help regulate temperature, regulate humidity (because too wet and stone deterioration, too dry and it causes health problems), and prevent the system waste of cold outside air coming in. The other part is to introduce a hypocaust for radiant heating/cooling, which has the added benefit of less needed excavation so that the mountain can preserve as much of its integrity as possible.

Using the hydroelectric dam from the underground river, the mechanical parts of the ventilation system can be hooked up to the electrical grid of Erebor (and adding in several alternating current generators can ramp up the electricity gained from the river generator to boost this without the need of a fuel source – useful in case of droughts) so that it can run by itself with little interference from engineers or mechanics aside from maintenance. Because the air ventilation system I’ve noted here makes use of a heat exchange system, the issue of cold outside air becomes much less of a problem – especially if you’re making use of the forges to run the pipes of air/steam by and heat those up. They can be cooled down by having the pipes returning to the forges run through some cool part of the mountain – by the river, likely, since it’s a stable temperature and can create a convenient loop whereby any cleaning of used pipe water (for bathwater, whatnot) can be dumped right back into the river so as to prevent draining the nearby lake.

Here’s an [example](http://t.umblr.com/redirect?z=http%3A%2F%2Fwww.passipedia.org%2Fplanning%2Fbuilding_services%2Fventilation%2Fbasics%2Ftypes_of_ventilation&t=NjczMWFlNjVhNDA1NzhmODVkMTJmNDJjZGNlMDFiODc0ZjgxYjE3NCxrRkQ2QUdZZQ%3D%3D&b=t%3AYnEewNG4oBRl9M0gUhrDsA&p=http%3A%2F%2Ftexasdreamer01.tumblr.com%2Fpost%2F121177889400%2Fmotherfuckingbagginshield-inja-y-ddraig&m=1) of heat recovery in a ventilation system that uses cross-flow to regulate air temperatures:

This is a counterflow principle that recuperates nearly 75% to 90% of the heat, which is good if you don’t want your pipes cooling down long before they can circulate back to the forges and thus create large pockets of cold air in Erebor that will leave many people freezing.

What can be done to regulate the temperature of the air pipes is exactly the same thing that can be done for the pipes of steam and air, so there’s not only a continuous supply of hot water in the mountain, but also a cheap and efficient means of _heating and cooling_ the mountain. This is done by implementing a radiant floor system – the most famous example is the Roman hypocaust used in villas and bath houses.

The reason why I suggest a water-based system of room temperature regulation instead of an air-based one is for a few reasons. For one, everything’s going to be in a pipe, anyway, so that gets rid of the contention point of water eroding stone over time. For two, water has a higher specific heat capacity than air, which means that it can hold on to temperatures for longer. For three, acquiring enough air to circulate throughout the entire mountain in an intricate set of pipes presents the difficulty of preventing it from exploding it on you by accident because it’s a very delicately-balanced system.

Using temperature-regulated piped water is known as [hydronics](http://t.umblr.com/redirect?z=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FHydronics&t=M2EzZjJkMTJmNGM1MTU2Nzg2MWYzZWIxOGM2NDk0NWZlMDk5N2VmMCxrRkQ2QUdZZQ%3D%3D&b=t%3AYnEewNG4oBRl9M0gUhrDsA&p=http%3A%2F%2Ftexasdreamer01.tumblr.com%2Fpost%2F121177889400%2Fmotherfuckingbagginshield-inja-y-ddraig&m=1), and its most familiar example is a radiator. A sub-floor heating/cooling system is basically sticking the radiator under the floor. It’s a very old system – the earliest known use comes from Manchuria and Korea about seven thousand years ago, so it’s certainly feasible to apply to Middle Earth technologies considering that they don’t appear to be highly dependent on electricity to sustain themselves.

I’m going to argue for a water loop system instead of a system that relies on the piping of steam for the singular reason that we can also use the exact same pipes for air conditioning. [Wikipedia](http://t.umblr.com/redirect?z=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FHydronics%23Water_loops&t=N2I3ZWMyNTZlOTQzOWYyZDI0ZGI2ZTE4YjBkYmZmNjM0YjU0MTdlMixrRkQ2QUdZZQ%3D%3D&b=t%3AYnEewNG4oBRl9M0gUhrDsA&p=http%3A%2F%2Ftexasdreamer01.tumblr.com%2Fpost%2F121177889400%2Fmotherfuckingbagginshield-inja-y-ddraig&m=1) explains all of this better:

> Modern systems almost always use heated water rather than steam. This opens the system to the possibility of also using chilled water to provide [air conditioning](http://t.umblr.com/redirect?z=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FAir_conditioning&t=ODNiOTA3ZjgyMmE4NTc4MmU2YzgwZTEyYzg0NDJmZGQ1NDliOTYwNixrRkQ2QUdZZQ%3D%3D&b=t%3AYnEewNG4oBRl9M0gUhrDsA&p=http%3A%2F%2Ftexasdreamer01.tumblr.com%2Fpost%2F121177889400%2Fmotherfuckingbagginshield-inja-y-ddraig&m=1).
> 
> In homes, the water loop may be as simple as a single pipe that “loops” the flow through every radiator in a zone. In such a system, flow to the individual radiators cannot be modulated as all of the water is flowing through every radiator in the zone. Slightly more complicated systems use a “main” pipe that flows uninterrupted around the zone; the individual radiators tap off a small portion of the flow in the main pipe. In these systems, individual radiators can be modulated. Alternatively, a number of loops with several radiators can be installed, the flow in each loop or zone controlled by a [zone valve](http://t.umblr.com/redirect?z=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FZone_valve&t=YWJkZDJjNWVlNjYxZGI4ZjAzYmRiZWEyMTZhODliZjA0YTNmNmFhZixrRkQ2QUdZZQ%3D%3D&b=t%3AYnEewNG4oBRl9M0gUhrDsA&p=http%3A%2F%2Ftexasdreamer01.tumblr.com%2Fpost%2F121177889400%2Fmotherfuckingbagginshield-inja-y-ddraig&m=1) connected to a [thermostat](http://t.umblr.com/redirect?z=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FThermostat&t=OWU0ODhlYjlhYTE0NDJhOGY4YWZmNDJhNDEzMTI0YTcxNTU5NTY5MSxrRkQ2QUdZZQ%3D%3D&b=t%3AYnEewNG4oBRl9M0gUhrDsA&p=http%3A%2F%2Ftexasdreamer01.tumblr.com%2Fpost%2F121177889400%2Fmotherfuckingbagginshield-inja-y-ddraig&m=1).
> 
> In most water systems, the water is circulated by means of one or more [circulator pumps](http://t.umblr.com/redirect?z=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FCirculator_pump&t=NTNjNWExYWFkYTcwODNkYWU0NTQ1YWYwYjZhYTg3ODkxMjQ3NWZkNixrRkQ2QUdZZQ%3D%3D&b=t%3AYnEewNG4oBRl9M0gUhrDsA&p=http%3A%2F%2Ftexasdreamer01.tumblr.com%2Fpost%2F121177889400%2Fmotherfuckingbagginshield-inja-y-ddraig&m=1). This is in marked contrast to steam systems where the inherent pressure of the steam is sufficient to distribute the steam to remote points in the system. A system may be broken up into individual heating _zones_ using either multiple circulator pumps or a single pump and electrically operated [zone valves](http://t.umblr.com/redirect?z=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FZone_valve&t=YWJkZDJjNWVlNjYxZGI4ZjAzYmRiZWEyMTZhODliZjA0YTNmNmFhZixrRkQ2QUdZZQ%3D%3D&b=t%3AYnEewNG4oBRl9M0gUhrDsA&p=http%3A%2F%2Ftexasdreamer01.tumblr.com%2Fpost%2F121177889400%2Fmotherfuckingbagginshield-inja-y-ddraig&m=1).

A system like this means that residential areas, guilds, kitchens, etc, can all have specialized temperature adjustments according to their needs. Water loop systems do have the problem of air bubbles and dissolved air, but keeping a careful eye on it reduces most troubles. As an added benefit, the water used to heat/cool the mountain can also be piped to bathing chambers and water faucets en route to the waste recycling before it gets piped back into the river, so it’s capable of being very efficient and reducing the need to add in extra pipes just for things like toilets.

The communications system, by the way, would be an air-pressure powered chutes system, like the ones you see at some banks in the drive-through. There would most likely be pit stops to sort the mail and to compensate for the eventual drop in air pressure in the pipes, but that means that each section of the mountain can essentially have its own post office. Not too good for anything that won’t fit in the container, but it can take care of most correspondence like letters, flyers, and the like (spam mail in Middle Earth, you don’t say).

Transportation can function in much the same way, if you’re alright with a larger chute system that hurtles you from one end of Erebor to the other in five minutes flat. Of course, an electrically-powered metro or lift (that will probably end up looking a lot like a Ferris wheel on a belt, if only so that multiple people can ride at the same time) can also be done; elevators, then, are also probably a thing – dinging optional.

FOOD. Okay, this one’s cool, I swear. You don’t actually need sunlight, if you have a suitable light source! And fish. Definitely need the fish, trust me on this.

If those pretty strings of fairy lights we see in the movie don’t produce enough lumens, then incandescent light bulbs could work (or some form of CFL, if not LEDs entirely – because if anyone can find and figure out noble gases, I’m pretty certain it’s dwarves). Plants do need a lot of light, but if you can’t either trade for your food or grow it in a greenhouse on the slopes, then producing enough wattage with your artificial light is a must. That aside, it’s actually a pretty easy setup – you don’t even really need dirt, if you don’t feel like it.

Here are a couple examples of what an aquaponics system can look like (by no means every single design, but some scales for comparison):

You’re going to need a compost heap for this to work, but lucky for us mountains are perfectly capable of providing cool, dark places to make the worms happy. Turning it is a good chore for an apprentice, too.

Borrowing some fish from either the River Running or the lake is enough, and truly you don’t even need that many to begin with – it’s a good way to secure some meat without needing to go outside the mountain, too, which is good during especially cold winters or when your trade partners are being particularly obstinate. (Sometimes you can let the fish nibble on the roots to feed them, but you need to be careful with that in case they decide to get too hungry.)

It needs very little tending, and you can grow a variety of plants – even put it in a greenhouse! That makes Erebor pretty self-sufficient, with a lot of room for technological advances, population growth, etc. Livestock and their products (meat, milk, cheese, butter, etc) will probably have to be traded for unless they happen to keep pens at the foot of the mountain.

**Author's Note:**

> This series will be posted first on tumblr under the tag #Erebor Engineering. Drop a line on my [tumblr](http://texasdreamer01.tumblr.com/)!


End file.
